Menstruation, in common language, "is the natural bodily process of releasing blood and associated matter from the uterus through the vagina as part of the menstrual cycle." This cycle generally happens every month.
Although periods are normal, we hesitate to talk about it, we can even say we are not allowed to talk. In some contexts, girls and people who menstruate face restrictions when they are on their periods, for example: they are not allowed to go out, they are not allowed to play, they are not allowed to touch this or that and more importantly they are not allowed to share about this matter to the men in their household. A girl who has her first menstruation is many times made to believe that it's not a good thing and that you can become impure.
Even today, when I go to buy pads I am given the sanitary pads wrapped in a paper and in a plastic bag. Buying a sanitary pad is not illegal. It's a need for me, for you and for every girl out there. Many times I have seen people making faces when a boy goes to buy a pad. Till today our society hesitates to say "periods" or "menstruation", they sometimes prefer to call it a "girls problem". Let me correct them: "IT'S NOT A PROBLEM". Having a period indicates a healthy women or person.
There must be no shame for anyone to openly talk about periods, be it at school, home or in any environment. Girls, women and menstruating persons during their menstruation must be provided with such environment where they can openly share how they feel.
Menstruation is a topic every father, every brother, every husband, every boyfriend, every man and every person must be familiar with. Menstruation is part of our health and not part of a sin.